Sum of two squares theorem
= Sum of two squares theorem
{wiki=Sum_of_two_squares_theorem}
The Sum of Two Squares Theorem states that a positive integer \\( n \\) can be expressed as a sum of two squares (i.e., \\( n = a^2 + b^2 \\) for some integers \\( a \\) and \\( b \\)) if and only if in its prime factorization, every prime of the form \\( 4k + 3 \\) appears with an even exponent.